1. Field of the Invention
This invention relates to a distributed data processing system comprising several local systems (LS) 10, each of sid LS (10) comprising at least one processing unit (36) with the associated stores, peripherals (30 to 32) and processes and a local monitor (37 to 41), said LSs (10) communicating via a general communications network.
2. Description of the Prior Art
Technological progress in the field of integrated circuits (LSI) and their low cost have resulted in an evolution in the architecture of data processing systems towards distributed systems. There are now processors categories such as control processing units CPU) reserved exclusively for the users, processors oriented towards system management (resource allocation, data base management, communications, etc.) and service processors.
Moreover, the local interconnection of distributed data processing systems situated at an organization's premises having as objectives communication and resource sharing, has resulted in the creation of procedures and protocols to allow the initialization of distributed systems, communications between applications and the optimum use of resource sharing between them.
All the references listed in the appendix are of a general nature. In reference (1), the distributed control of the overall system resides in each of the LSs, which are processors with a main store in this instance. References (2) and (3) describe a distributed communications network for the transmission of data in packets in which the user programs and resources are shared. In this system, however, all the units are placed in a "bus" hierarchy. References (4) to (7) describe either distributed processing (reference 4) or distributed control (references 5 and 6), or the sharing of all the components of a system. In the present invention, the various functions of a distributed system are separated from the LS and are located in their respective functional layers; e.g. the coordination functions (sharing of resources between the LS, etc.) are located in the functional coordination layer and managed by systems intercommunications processors (SIP), the communications procedures between the LS are located in the functional communications layer and managed by the communication modules CM, and the elements required for physical transmission on an optical bus between the LS are located in the functional transport layer and are managed by the TM (Transmission Modules) and the LIG (Looping Unit).